Earth observation satellites collect large amounts of data, while transmission capacities to earth are limited. Special computers, known as Data Processing Units (DPUs), store, analyze and compress this data directly on board of the satellite - efficiently and reliably. 

The Fraunhofer Institute for High-Speed Dynamics EMI in Freiburg has been researching and developing DPUs for small satellites since 2014. On January 14, the research institute's latest and most powerful DPU was launched into orbit on board constellr's Sky-Bee-1 earth observation satellite. constellr is a spin-off of the Fraunhofer EMI.

DPU: the brain of the payload

The DPU measures approx. 10 cm x 9 cm x 6 cm and weighs around 840 grams. It is the central computer for the satellite payloads, consisting of a VNIR instrument with ten spectral bands and a TIR camera with four spectral bands in the range between 8 and 12 µm. They provide continuous data on the land surface temperature, which is relevant for agriculture, for example.

The DPU processes, stores, and transmits the image data. It also controls and monitors the payloads. The software can be reconfigured during the mission and offers a high degree of automation and operational flexibility. The system uses commercial components (COTS) and is therefore inexpensive to manufacture. It also uses modern FPGA-based processors that provide the necessary performance for high-resolution cameras and advanced algorithms.

High reliability through redundancy 

The DPU hardware has a redundant design. All internal components are available at least twice, so that in the event of a fault it is possible to switch to the replacement component. The COTS-based system therefore meets the high requirements of a commercial earth observation mission.

Numerous software measures also contribute to increased reliability in orbit. For example, the entire software is stored in a total of 18 copies on six different memory modules.

The DPU has been qualified in accordance with the »European space standards European Cooperation for Space Standardization« with regard to vibrations and thermal vacuum environment.

»The data processing unit is a powerful and cost-efficient research product of the Fraunhofer-Gesellschaft - optimally tailored to the needs of our industrial customers in the space sector. We would like to thank constellr for their trust in using our innovative technology,« says Prof. Frank Schäfer, Head of the Space Business Unit at Fraunhofer EMI.

Further development with AI components 

Fraunhofer EMI is already working on the next generation of the DPU. This integrates AI-based algorithms to classify image data in orbit and in real time in the future. »Companies and applications from NewSpace need both powerful and reliable solutions as well as fast development cycles. We combine both with our DPUs and are already looking forward to using the next generations of our technology,« says Clemens Horch, DPU project manager at Fraunhofer EMI.